Hello Ria Saraf,
I am also in the same position. My articleship completed on Dec'10. I have sent Form 108 to the Institute But I didnt received the Confirmation Letter still now. I contact SIRC Chennai Branch - Articles Section regarding this matter. They said that, If your confirmation letter is not yet received you can enclose Photostat copy of Form-108 along with Online application form.
But Dont fill the Wrong Column(Second Column) i.e. Mentioning you are in the last 6 Months of Articleship Training...
Just Fill the First Column and Write the Words "Confirmation Letter not yet received Hence photostat copy of Form 108 enclosed"